Add missing directives to the `schema` folder

[abensonca]

The schema folder contains XSD files used to validate embedded XML directives in Galacticus source files. Several common directives lack schemas, meaning they are silently skipped during validation. These missing directives should have entries added to schema to ensure they are validated. Missing directives are:

• allocate
• conditionalCall
• deepCopy
• deepCopyActions
• deepCopyFinalize
• deepCopyReset
• dependenciesInitialize
• eventHook
• eventHookManager
• eventHookStatic
• expiry
• forEach
• functionClass
• functionGlobal
• generic
• metaPropertyDatabase
• objectBuilder
• optionalArgument
• outputFileClose
• outputFileOpen
• parameterMigration
• referenceCountIncrement
• scoping
• sourceDigest
• stateRestore
• stateStorable
• stateStore
• workaround

[abensonca]

outputFileOpen and outputFileClose come from eventHookStatic. We can identify any eventHookStatic directive and apply the same schema to it - just has a function attribute.

[abensonca]

Similarly, for any functionClass instance we can automatically detect and apply the same schema.